Simultaneous casting and trimming apparatus



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Sept. 3,1957 H.'W. BARTHOILQMEW 2,804,662

SIMULTANEOUS CASTING AND TRIMMING APPARATUS Filed July 29, 1955 6Shee'ts-Sheet 1 I s INVENTOR.

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IITTORNEY Sept. 3, 1957 H. w. BARTHOLOMEW 2,804,662 SIMULTANEO USCASTING AND TRIMMING APPARATUS Filed- Ju1y'29, 1955 6 Sheets-Sheet 6 QEE VN 9:1 2.5m

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SIMULTANEOUS CASTING AND TRIMMING APPARATUS Howard W. Bartholomew,Pottstown, Pa., assignor to National Lead Company, New York, N. Y., acorporation of New York Application July 29, 1955, Serial No. 525,203

Claims. (Cl. 22-57) This invention relates to means for pressure diecasting. More specifically it relates to apparatus for simultaneouslycarrying out casting and trimming operations.

In the production of cast pieces by pressure die casting methods, it iscustomary to force a charge of molten metal under pressure into asuitable die. The molten metal in the die is allowed to cool and thussolidify into a solid casting. The casting, however, normally hasattached to it some extraneous solidified metal known as gate" and/ orflashing which must be removed in order to finally obtain a finishedcasting having the desired configuration. The gate and/ or flashing isin part sometimes deliberately formed in order to support the castingand provide area for contacting ejecting pins and the like and is alsoin part an inherent result of the pressure die casting technique. Whenemploying pressure die casting methods to produce large numbers ofidentical pieces and in particular when very small castings areproduced, it becomes extremely important from the economical view pointto produce the finished trimmed cast piece with a minimum amount ofhanding.

Accordingly, an object of the instant invention is to provide means forsimultaneously casting and trimming pieces of some desiredconfiguration. Another object is to provide apparatus which permitspressure die casting of a piece and simultaneous trimming of anidentical piece which has just been cast. Another object is theprovision of apparatus unitarily arranged for carrying out casting andtrimming operations in an integrated and eflicient manner. Still anotherobject is to provide an improved apparatus for casting a plurality ofsmall pieces and for trimming the flashing therefrom. These and otherobjects of the instant invention will become evident from the followingmore complete description and from the drawings.

Broadly, the simultaneous casting and trimming operation as hereincontemplated is made possible by the construction of apparatusincorporating a movable carrier bar which supports the casting as formedand transfers it to a trimming station positioned adjacently to thecasting die. This principle is more clearly demonstrated by consideringthe drawings wherein briefly:

Fig. 1 represents a vertical side view of apparatus according to theinstant invention, and

Fig. 2 taken along line 2-2 of Fig. 1 shows in front elevation a typicalcover die as hereinafter more fully described.

Fig. 3 taken along line 33 of Fig. 1 illustrates the details of thepassage provided for introduction of molten metal into the assembleddie.

Fig. 4 taken along line 44 of Fig. 1 shows in front elevation a typicalejector die and the carrier bar which when assembled in contact with thecover die shown in Fig. 2 form a completed die.

Fig. 5 taken along line 5-5 of Fig. 4 shows a horizontal construction ofsuitable gate ejecting pins asis know to the art.

nited. States Patent Figs. 6-8, all in side elevation, show in sequencethe relative positions of the cover die, the ejector die, and thecarrier bar during stages of the casting and trimming operation.

Fig. 9 shows the carrier bar in cross section partially cut away.

Fig. 10 shows a typical assembly of small cast pieces as may beinitially produced with the flashing still surrounding each piece andFig. 11 shows in front elevation a trimmed casting from Fig. 10.

Fig. 12 shows schematically a top view of typical apparatus employingthe instant principle including a casting station and two adjacentlypositioned trimming stations.

Figs. 13-21 are schematic top views of the apparatus as identified inFig. 12 and show sequentially the relative position of the parts as anoperational cycle is conducted.

Considering now the drawings in some greater detail in Fig. 1 there isshown carrier bar 10, cover die 12, and ejector die 14 which parts areoperably positioned generally between front plate 16 and movable backplate 18. Cover die 12 as more clearly shown in Fig. 2 is a stationarypart and is provided with a plurality of recessed cavities 20 into whichdie sections can be inserted and retained. Of course this constructionis not limited to the particular die section as illustrated. Othermodifications including provisions for casting more or fewer pieces aswell as larger or smaller pieces is also contemplated as being withinthe scope of this invention. The cover die is provided with passageway22 which opens into sprue plug 24 of carrier bar 10 and thus permits ashot of molten metal to be introduced by suitable means, not shown, intothe assembled die.

The construction of carrier bar 10 and its relationship to the ejectordie 14 can be better appreciated by considering Fig. 4, Fig. 5, and Fig.9. The carrier bar 10 is of generally rectangular shape and ishorizontally movable in two directions. It is capable of movement to andaway from the cover die and can also index or move in a direction normalto such movement. According to the instant construction the carrier baris provided with two sprue plugs 24 which have a number of functions.The sprue plug permits introduction of the molten metal through gaterunners 26 and into the die interior. The sprue opening is also filledwith metal in the casting operation as is shown in Fig. 10 and the sprueplug then acts as a support for the casting. The casting so supported bythe sprue plug 24 of the carrier bar 10 may then be moved to a trimmingstation 36. The two sprue plugs 24 are so positioned relative to oneanother that while the one supports a casting at the trimming station 36the other will be aligned with the passageway 22 of cover die 12 andthus permit casting of another piece. As indicated carrier bar 10 isprovided with gate ejecting means such as sprue ejectors 28. These pinswhich may be constructed as is known to the art are positioned in thevicinity of sprue plugs 24 and'are employed to eject the gate 30 fromthe sprue plug thereby permitting the gate and flashing to be discardedfrom the apparatus after the cast pieces have been trimmed.

As shown in Fig. 4 carrier bar 10 and ejector die 14 contact one anotheralong parting line AA and when so positioned form one side of the dieassembly, the surfaces of which are arranged for close and matchingcontact with cover die 12. By appropriate movement either sprue plug 24-of carrier bar 10 can be positioned for contacting the ejector die asshown.

As is shown schematically in Figs. l22l two trimming stations 36 arepositioned equidistant on either side of the casting station. Theparticular trimming means which may be employed is not limited vandthose which are known in the art are generally suitable. For example atrimming die 38 comprising a stationary block having holes identical inshape to the periphery of the casting may be employed. Suitable trimmingpunches 40 may be employed in cooperation with the trimming die 38whereby the finished casting may be punched out :from the surroundingflashing. It has been found desirable to employ a stripper plate 42 toassist in supporting the gate assembly while trimming and for aiding inthe stripping of the gate or flashing from the carrier bar as mentionedpreviously.

A typical operational cycle will now be described. Reference is made toFigs. 6-8 for the relative movement of the carrier bar 10, cover die 12,and ejector die 14. Also Figs. 12-21 will show the sequential movementand positioning of the castings in relation to the casting and trimmingstations. Consider now that the cover die 12, and carrier bar 10, andejector die 14 are all in fully closed position as shown in Fig. 13.Molten metal such as for example zinc or aluminum or alloys thereof isforced under pressure into the die cavity. After a predetermined periodsufiicient to permit solidification of the molten metal the openingcycle starts.

The ejector die 14, ejector pins 32, carrier bar which supports thegated casting, all being in intimate contact begin to move away from thecover die 12 for a predetermined distance say /2 inch. (See Fig. 6 andFig. 14.)

The carrier bar it) then stops. The ejector pins 32 also stop. The gatedcasting which is held in the carrier bar and is additionally supportedby the ejector pins also stops. The ejector die 14, however, does notstop but continues back for an additional distance, for example inchmore. See Fig. 7 and Fig. 15. The rearward movement of carrier bar 10 iscontrolled by appropriate means such as for example carrier bar stop 34.

The ejector die continues to move back for a still additional distanceof say 4 inch (thus having moved typically for a total opening of oneinch), and in so doing carries the ejector pins away from the gate. (SeeFig. 8.) This movement leaves the gated casting supported only by thecarrier bar. In a typical operation the ejector pin mechanism is springloaded during the final movement inch) of the ejector die 14.

The carrier bar then indexes or moves to the trimming station in adirection normal to its opening motion. (See Fig. 16.) This movement isaccomplished by conventionalmeans as will be appreciated by thoseskilled in the art. After moving the gated casting as indicated, thecarrier bar 10 now moves into the trimming position. This movementaccording to the example used herein will be for a distance of /2 inchtoward the cover die 12 or trimming die J8 a shown in Fig. 17. Thecasting is now in intimate contact with the trim die plate 38 and thesecond sprue plug 24 of carrier bar 10 is in contact with the cover die12 and coincides with passageway 22. Simultaneously with such movementof the carrier bar it), the ejector die 14 is moving into closedposition (for example for a distance of one inch). The ejector pins 32automatically are placed in proper position during thi movement byvirtue of the spring loading previously mentioned.

As indicated in Fig. l the ejector die is attached to movable supportback 18. Trimming punches 40 are arranged in fixed position to themovable back plate 18 and move with the back plate and relative to theejector die 14. When the ejector die 14 is against the cover die 12 thetrimming punches 40 are against the castings but have not yet punchedthem from the gate and flashing.

The stripper plate 42 is also spring loaded and is arranged to moverelative to the ejector die 14 and to the trimming punches 40 and movesagainst the gated casting so as to support same. (See Fig. 17.)

The apparatus is now assembled for formation of another casting and fortrimming of the pieces which have just been cast. Simultaneously withthe introduction of .4 another shot of molten metal into the die cavity,the trimming punches 40 are activated and are pushed forward (forexample about 7 inch). This action punches out the finished casting asshown in Fig. 18.

Gate ejecting means such as sprue ejectors 28 are located on either sideof the sprue plug in the carrier bar and are arranged to force-the gatefrom the carrier bar. This action is in effect simultaneous with thetrimming. As the carrier bar it) once again begins to open away from thecover die 12 and trimming die 38 the gate falls free from the apparatusassisted by the action of the stripper plate 42 on its opening cycle.

The cycle just described is then again repeated as shown in Figs. 18-21.However, as will be appreciated the carrier bar is now indexed so as tomove the cast piece to the trimming station opposite that employed asjust mentioned.

it is evident from the preceding description and from the drawings thatthe instant die casting apparatus wherein the unique carrier bar isincorporated represents a definite advance to the die casting art.Although the principle of operation is not restricted to any sizecasting, it is obvious that apparatus of the instant type can greatlyincrease the yield of small castings for any given time period.

While this invention has been described above and shown in the drawings,it is not meant to be limited thereto and is intended to include allthose devices coming within the scope of the following claims.

I claim:

1. Simultaneous casting and trimming apparatus comprising a pressurecasting station and two trimming stations which are horizontallypositioned on opposite sides of said casting station, said castingstation including a stationary cover die, a movable ejector die, and acarrier bar of generally rectangular shape and being movable to and awayfrom the cover die and also being movable in a direction normal thereto,said carrier bar having a pair of identical sprue openings forsupporting a pressure die casting and for transporting same to one ofthe trimming stations.

2. Simultaneous casting and trimming apparatus comprising a pressurecasting station and two identical trimming stations which arehorizontally positioned equidistant on opposite sides of said castingstation, said casting station including a stationary cover die, amovable ejector die, and a carrier. bar of generally rectangular shapeand being movable to and away from said cover die and also being movablein a direction normal thereto, said carrier bar having a pair ofidentical sprue openings for supporting a pressure die casting and fortransporting same to one of the trimming stations.

3. Simultaneous casting and trimming apparatus comprising a pressurecasting station and two identical trimming stations which arehorizontally positioned equidistant on opposite sides of said castingstation, said casting station including a stationary cover die, amovable ejector die, and a carrier bar of generally rectangular shape,said carrier bar being movable to and away from said cover die and alsobeing movable in a direction normal thereto, said carrier bar being ofsuch length so as to extend from the casting station to either of thetrimming stations, said carrier bar having a pair of identical sprueopenings for supporting pressure die castings, said sprue openings beingpositioned so that one is at the casting position when the other is atthe trimming position.

4. Simultaneous casting and trimming apparatus comprising a pressurecasting station and two identical trimming stations which arehorizontally positioned equidistant on opposite sides of said castingstation, said casting station including a stationary cover die having apassageway for introduction of molten metal into the die cavity, amovable ejector die, and a movable carrier bar so arranged in contactwith said ejector-die as to form one side of the die assembly when inclosed position, said carrier bar having a pair of identical sprueopenings for supporting pressure die castings, said carrier bar designedfor horizontal movement between the casting station and the trimmingstations in such manner as to permit simultaneous casting and trimmingoperations.

5. Simultaneous casting and trimming apparatus comprising a pressurecasting station and two identical trimming stations which arehorizontally positioned equidistant on opposite sides of said castingstation, said casting station including a stationary cover die having apassageway for introduction of molten metal into the die cavity, amovable ejector die, and a movable carrier bar so arranged in contactwith said ejector die as to form one side of the die assembly when inclosed position, said carrier bar having a pair of identical sprueopenings capable of supporting pressure die castings, said ejector dieand carrier bar being movable to and away from said cover die, saidcarrier bar further being movable in a direction normal to said coverdie and between said casting station and said trimming stations, thesprue openings of said carrier bar being positioned relative to oneanother so that one is at the casting position when the other is at thetrimming position, means for trimming the casting, and coordinated meansfor forming another casting simultaneously with said trimming.

References Cited in the file of this patent UNITED STATES PATENTS457,879 Madden Aug. 18, 1891 1,570,658 Wickland et a1. Jan. 26, 19261,815,361 Morris et al July 21, 1931 2,058,762 Bible Oct. 27, 19362,076,374 King Apr. 6, 1937 2,367,303 Morin Jan. 16, 1945 2,494,777Patterson et a1 Jan. 17, 1950 2,569,083 Wilhelm Sept. 25, 1951 2,704,388West at al Mar. 22, 1955 FOREIGN PATENTS 641,858 Great Britain Aug. 23,1950

